An Introduction to Quantum Spin Systems [Paperback]

The topic of lattice quantum spin systems is a fascinating and by now well established branch of theoretical physics. Based on a set of lectures, this book has a level of detail missing from others, and guides the reader through the fundamentals of the field.

Spin Models.- Quantum Treatment of the Spin-? Chain.- The Antiferromagnetic Ground State.- Antiferromagnetic Spin Waves.- The XY Model.- Spin-Wave Theory.- Numerical Finite-Size Calculations.- Other Approximate Methods.- The Coupled Cluster Method.- Quantum Magnetism.The topic of lattice quantum spin systems is a fascinating and by nowwell-established branch of theoretical physics. However, many importantquestions remain to be answered. Their intrinsically quantum mechanicalnature and the large (usually effectively infinite) number of spins inmacroscopic materials often leads to unexpected or counter-intuitiveresults and insights. Spin systems are not only the basic models for awhole host of magnetic materials but they are also important as prototypicalmodels of quantum systems. Low dimensional systems (as treated in this primer),in 2D and especially 1D, have been particularly fruitful because theirsimplicity has enabled exact solutions to be determined in many cases.These exact solutions contain many highly nontrivial features.This book was inspired by a set of lectures on quantum spin systems and it isset at a level of practical detail that is missing in other textbooks in the area. Itwill guide the reader through the foundations of the field. In particular, the solutionsof the Heisenberg and XY models at zero temperature using the Bethe Ansatzand the Jordan-Wigner transformation are covered in some detail. The use ofapproximate methods, both theoretical and numerical, to tackle more advancedtopics is considered. The final chapter describes some very recent applicationsof approximate methods in order to show some of the directions in which thestudy of these systems is currently developing.Veló+